 /*******************************************************************************
  * Copyright (c) 2000, 2005 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.core.filebuffers.manipulation;

 import java.util.Map ;

 import org.eclipse.core.internal.filebuffers.FileBuffersPlugin;
 import org.eclipse.core.internal.filebuffers.Progress;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IPath;
 import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.OperationCanceledException;
 import org.eclipse.core.runtime.Status;

 import org.eclipse.core.filebuffers.IFileBuffer;
 import org.eclipse.core.filebuffers.IFileBufferStatusCodes;
 import org.eclipse.core.filebuffers.ITextFileBuffer;

 import org.eclipse.text.edits.TextEdit;

 import org.eclipse.jface.text.BadLocationException;
 import org.eclipse.jface.text.DocumentRewriteSession;
 import org.eclipse.jface.text.DocumentRewriteSessionType;
 import org.eclipse.jface.text.IDocument;
 import org.eclipse.jface.text.IDocumentExtension4;
 import org.eclipse.jface.text.TextUtilities;

 /**
  * Abstraction for a file buffer operation that works on text file buffers.
  * Subclasses have to override the <code>computeTextEdits</code> method in
  * order to provide a sequence of {@link org.eclipse.text.edits.TextEdit}
  * objects.
  *
  * @since 3.1
  */
 public abstract class TextFileBufferOperation implements IFileBufferOperation {


     /**
      * Computes and returns a text edit. Subclasses have to provide that method.
      *
      * @param textFileBuffer the text file buffer to manipulate
      * @param progressMonitor the progress monitor
      * @return the text edits describing the content manipulation
      * @throws CoreException in case the computation failed
      * @throws OperationCanceledException in case the progress monitor has been set to canceled
      */
     protected abstract MultiTextEditWithProgress computeTextEdit(ITextFileBuffer textFileBuffer, IProgressMonitor progressMonitor) throws CoreException, OperationCanceledException;

     /**
      * Returns the rewrite session type that corresponds to the text edit sequence.
      *
      * @return the rewrite session type
      */
     protected abstract DocumentRewriteSessionType getDocumentRewriteSessionType();


     private String fOperationName;
     private DocumentRewriteSession fDocumentRewriteSession;

     /**
      * Creates a new operation with the given name.
      *
      * @param operationName the name of the operation
      */
     protected TextFileBufferOperation(String operationName) {
         fOperationName= operationName;
     }

     /*
      * @see org.eclipse.core.internal.filebuffers.textmanipulation.IFileBufferOperation#getOperationName()
      */
     public String getOperationName() {
         return fOperationName;
     }

     /*
      * @see org.eclipse.core.internal.filebuffers.textmanipulation.IFileBufferOperation#run(org.eclipse.core.filebuffers.IFileBuffer, org.eclipse.core.runtime.IProgressMonitor)
      */
     public void run(IFileBuffer fileBuffer, IProgressMonitor progressMonitor) throws CoreException, OperationCanceledException {

         if (fileBuffer instanceof ITextFileBuffer) {
             ITextFileBuffer textFileBuffer= (ITextFileBuffer) fileBuffer;
             IPath path= textFileBuffer.getLocation();
             String taskName= path == null ? getOperationName() : path.lastSegment();
             progressMonitor= Progress.getMonitor(progressMonitor);
             progressMonitor.beginTask(taskName, 100);
             try {
                 IProgressMonitor subMonitor= Progress.getSubMonitor(progressMonitor, 10);
                 MultiTextEditWithProgress edit= computeTextEdit(textFileBuffer, subMonitor);
                 subMonitor.done();
                 if (edit != null) {
                     Object stateData= startRewriteSession(textFileBuffer);
                     try {
                         subMonitor= Progress.getSubMonitor(progressMonitor, 90);
                         applyTextEdit(textFileBuffer, edit, subMonitor);
                         subMonitor.done();
                     } finally {
                         stopRewriteSession(textFileBuffer, stateData);
                     }
                 }
             } finally {
                 progressMonitor.done();
             }
         }
     }

     private Object startRewriteSession(ITextFileBuffer fileBuffer) {
         Object stateData= null;

         IDocument document= fileBuffer.getDocument();
         if (document instanceof IDocumentExtension4) {
             IDocumentExtension4 extension= (IDocumentExtension4) document;
             fDocumentRewriteSession= extension.startRewriteSession(getDocumentRewriteSessionType());
         } else
             stateData= TextUtilities.removeDocumentPartitioners(document);

         return stateData;
     }

     private void stopRewriteSession(ITextFileBuffer fileBuffer, Object stateData) {
         IDocument document= fileBuffer.getDocument();
         if (document instanceof IDocumentExtension4) {
             IDocumentExtension4 extension= (IDocumentExtension4) document;
             extension.stopRewriteSession(fDocumentRewriteSession);
             fDocumentRewriteSession= null;
         } else if (stateData instanceof Map )
             TextUtilities.addDocumentPartitioners(document, (Map ) stateData);
     }

     private void applyTextEdit(ITextFileBuffer fileBuffer, MultiTextEditWithProgress textEdit, IProgressMonitor progressMonitor) throws CoreException, OperationCanceledException {
         try {
             textEdit.apply(fileBuffer.getDocument(), TextEdit.NONE, progressMonitor);
         } catch (BadLocationException x) {
             throw new CoreException(new Status(IStatus.ERROR, FileBuffersPlugin.PLUGIN_ID, IFileBufferStatusCodes.CONTENT_CHANGE_FAILED, "", x)); //$NON-NLS-1$
 }
     }
 }

